Medical devices for subcutaneous use are known in the medical field. For example, biopsy needles are used to capture and remove internal tissues while avoiding invasive surgery. When performing medical procedures, often targeted bodily areas are surrounded by blood vessels or internal organs which can cause difficulties with accurate percutaneous positioning of medical devices. Imaging methods can mitigate some of these difficulties by providing for simultaneous imaging of internal organs and medical devices. Ultrasound imaging is particularly suitable due to its lesser operation cost and increased portability in comparison to other imaging modalities such as X-ray and MRI. During ultrasound imaging procedures, a transducer emits ultrasound waves. A portion of the ultrasound waves reflect when encountering organs, tissues, and other items inside the body and then return to the transducer. The returned sound waves are then used to produce a visual representation of an internal cavity. This provides a real-time moving image of the internal organs and medical device which a physician can use to guide the medical device to the desired bodily area.
Problems exist with current uses of ultrasound imaging to place a medical device subcutaneously because the image obtained through ultrasound is not always clear. However, there are ways to increase image clarity. Echogenic enhancements in the form of a matrix of depressions (i.e. dimples) in the surface of a medical device can cause an altered or improved reflective response of ultrasound waves. When applied to a medical device, echogenic enhancements can cause the medical device to have greater ultrasound image clarity. This in turn can increase positioning accuracy of the medical device.
Traditional methods of producing depressions on surfaces of medical devices are costly and time-consuming. For example, each reflected depression is commonly formed by using a punch to impact the surface of the medical device in order to create each individual dimple. After each punch strike, the needle is moved to the next point and another punch strike is made. The density of the matrix and, ultimately, the image quality of the device is limited by the number of punch strikes required to generate the matrix. This method is slow and can result in wasted time and costs, such as when a punch breaks and an entire batch of medical devices must be discarded. Other methods for creating a matrix of depressions can be used, such as by a laser ablation, particle (i.e. bead) blasting, or chemical machining. However, these methods are equally slow and offer lower echogenicity compared to punched dimples. Thus, there is a need for a method of producing echogenic enhancements on medical devices which is faster and less wasteful than traditional manufacturing methods, while also providing superior echogenicity.